Friday, May 30, 2008

Huge Flying Reptiles Ate Dinosaurs

A group of flying reptiles called Quetzalcoatlus may have strolled along a fern prairie eating baby dinosaurs for lunch. Credit: Mark Witton, University of Portsmouth.

With a name like T. rex, you'd expect to be safe from even the fiercest paleo-bullies. Turns out, ancient, flying reptiles could have snacked on Tyrannosaurus Rex babies and other landlubbing runts of the dinosaur world.

A new study reveals a group of flying reptiles that lived during the Age of Dinosaurs some 230 million to 65 million years ago did not catch prey in flight, but rather stalked them on land.

Until now, paleontologists pictured the so-called "winged lizards" or pterosaurs as skim-feeders. In this vision, the creatures would have flown over lakes and oceans grabbing fish from the water's surface, much as gulls do today.

The new findings, detailed this week online in the journal PLoS ONE, don't ground the animals totally.

"In our hypothesis, flight is primarily a locomotive method," said co-researcher Mark Witton of the University of Portsmouth in England. "They're just using it to get from point A to point B. We think the majority of their lives, when they're feeding and reproducing, that's all being done on the ground rather than in the air."

To uncover these feeding habits, Witton and Portsmouth colleague Darren Naish analyzed fossils of a group of toothless pterosaurs called azhdarchids, which are much larger on average than other pterosaurs. For example, one of the largest azhdarchids, Quetzalcoatlus, weighed about 550 pounds (250 kilograms) with a wingspan of more than 30 feet (10 meters) and a height comparable to a giraffe.

Witton and Naish learned that more than 50 percent of the azhdarchid fossils had been found inland. Other skeletal features, including long hind limbs and a stiff neck, also didn't fit with a mud-prober or skim-feeder.

"All the details of their anatomy, and the environment their fossils are found in, show that they made their living by walking around, reaching down to grab and pick up animals and other prey," Naish said.

A skim-feeder, such as a gull, trawls its lower jaw through the water, eventually smacking into a fish or shrimp and pulling it from the water. "Regardless of what they hit, the impact force drives the head and neck underneath the body and into the water, thus requiring a hugely flexible neck," Witton said.

This is the case with gulls and pelicans (which are considered plunge divers), but azhdarchid's neck, despite potentially reaching nearly 10 feet (3 meters) in length, was super stiff. "Whatever these animals were doing, it had to involve minimal neck action," Witton said.

Their tiny feet also ruled out wading in the water or probing the soft mud for food. "Some of these animals are absolutely enormous," Witton told LiveScience. "If you go wading out into this soft mud, and you weigh a quarter of a ton, and you've got these dinky little feet, you're going to just sink in."

The reptile's head also was pretty lengthy, up to 10 feet (3 meters). So Witton said an azhdarchid would only have to dip its head part way to the ground, enough for the tip of its jaws to touch down, to hunt and feed on terrestrial prey. Back before they went extinct 65 million years ago during the event that also killed off non-avian dinosaurs, these pterosaurs could lunch on animals ranging from small bird-like Velicoraptors to T. rex babies to amphibians

A gigantic bird-like dinosaur weighing as much as a car towered over its relatives about 70 million years ago, a new finding suggests.

The unearthed beaked dinosaur was not full-grown, yet it tipped the scales at more than 3,000 pounds. Paleontologists who discovered its remains estimate the behemoth was just 11 years old when it perished.

Chinese scientists unearthed the skeletal remains of the dinosaur, now named Gigantoraptor erlianensis, in the Erlian Basin of Inner Mongolia, China.

Oddly large

At up to 16 feet tall and 26 feet long, Gigantoraptor dwarfed its relatives, a group of small, feathered theropods called Oviraptorosaurs. The hefty dinosaur weighed 35 times more than other Oviraptorosaurs.

“It’s one thing to find a big dinosaur,” said Matthew Lamanna, assistant curator of vertebrate paleontology at the Carnegie Museum of Natural History, “but it’s another thing to find a big dinosaur from a lineage that was thought to be small.” Lamanna was not involved in the discovery.

In addition to its size, Gigantoraptor sported several bird-like features, such as a longer arm and more avian-like leg, not present in its relatives. The scientists say this finding sheds light on theropod (two-legged carnivorous dinosaurs) evolution leading to the emergence of birds.

Xing Xu of the Chinese Academy of Sciences in Beijing and Lin Tan of the Long Hao Institute in China, as well as their colleagues, discuss the finding in the June 14 issue of the journal Nature.

Oddly shaped

Gigantoraptor was also much ganglier than other dinosaurs. Typically, larger dinosaurs had proportionally stouter limbs and shorter lower legs than their smaller relatives. Relative to its size, Gigantoraptor had unusually slender limbs and lengthy legs.

Based on its close relationship to other feathered species, Gigantoraptor likely had feathers on its tail and arms, which were used as a display. While body-covering feathers act as insulation, and would have been necessary for the smaller dinosaurs, Gigantoraptor probably didn’t need such a cold protector, the scientists suggest.

“It’s unexpected discoveries like this that show, ‘Hey we know a lot about dinosaurs but there’s still so much left that we don’t know,’” Lamanna said.

Penguin Remains Being Used To Measure Antarctic Ice Movement

ScienceDaily (Jul. 23, 2007) — Climate change is nothing new. For thousands, perhaps millions of years, Antarctica's massive ice sheet - 5.5 million square miles - has advanced and retreated as the earth's atmosphere cooled and warmed. Yet, until recently, there was no precise way to measure the shifting interface between ice and open water.

By estimating the age of Adélie penguin remains using radiocarbon dating, University of North Carolina Wilmington Steven D. Emslie has determined a history of penguin colony locations that spans the last 45,000 years, the longest record now known for any species of penguin. He has charted the ancient penguin colonies' population shifts with climate change data and sea-ice extent to create a new and reliable method of dating ice movement.

Adélie penguins return to the same nesting site year after year and leave behind a wealth of debris, including bone, tissue, feathers, feces and eggshells, almost perfectly preserved in Antarctica's frigid, dry atmosphere. Emslie, a marine ornithologist in the Department of Biology and Marine Biology, has even found an entirely mummified penguin in the debris that dates to ~1000 years old. These penguin remains are the focus of two recent articles by Emslie, the second of which appeared as the cover story in the July 10 issue of the Proceedings of the National Academy of Sciences, a leading scientific journal in the U.S.

The first article describes the method Emslie developed to measure the advance and retreat of the Ross Ice Shelf, part of a large glacier that extends into the Ross Sea, by locating and dating the presence of Adélie penguin colonies. Published with Larry Coats and Kathy Licht in the January 2007 edition of Geology, and entitled "A 45,000 year record of Adélie penguins and climate change in the Ross Sea, Antarctica," the article examines the effects of climate change on Adélie penguins over millennia.

Adélie penguins are the smallest and most widely distributed penguins in Antarctica. They nest in ice-free areas along the coast of the open sea, their historical colonies marking the edge of the sea and its advancing and retreating ice sheets with the debris they leave behind. Using the locations of these ancestral colonies, Emslie determined that the Ross Ice Shelf advanced northward in the Ross Sea until about 13,000 years ago, when it began retreating at the end of the last ice age.

The Antarctic ice sheet plays a critical role in global climate control by reflecting sunlight into space and cooling the earth's temperatures and oceans.

The second article, published July 10, is a companion to the one published in Geology, and documents an apparent dietary shift in penguins that occurred 200 years ago in conjunction with the historic depletion of krill-eating seals and whales in the Southern Ocean. Adélie penguins are known to feed primarily on krill in Antarctica today. However, Emslie's research indicates that this krill diet is a recent adaptation to changing marine conditions, in this case brought about by humans. The former diet of penguins, prior to seal and whale depletions, was based on fish, a food resource also now depleted in the Southern Ocean. With krill biomass now undergoing large decreases as well, mainly due to the effects of human-induced climate warming and krill fisheries combined, the penguins are rapidly losing their options for prey.

Emslie's research has been funded by the National Science Foundation, the National Geographic Society and NASA.

University of North Carolina Wilmington. "Penguin Remains Being Used To Measure Antarctic Ice Movement." ScienceDaily 23 July 2007. 30 May 2008 /releases/2007/07/070721150332.htm>.

March Of The Giant Penguins: Prehistoric Equatorial Penguins Reached 5 Feet In Height

ScienceDaily (Jun. 25, 2007) — Giant prehistoric penguins? In Peru? It sounds more like something out of Hollywood than science, but a researcher from North Carolina State University along with U.S., Peruvian and Argentine collaborators has shown that two heretofore undiscovered penguin species reached equatorial regions tens of millions of years earlier than expected and during a period when the earth was much warmer than it is now.

Paleontologist Dr. Julia Clarke, assistant professor of marine, earth and atmospheric sciences at NC State with appointments at the North Carolina Museum of Natural Sciences and the American Museum of Natural History, and colleagues studied two newly discovered extinct species of penguins. Peruvian paleontologists discovered the new penguins' sites in 2005.

The research is published online the week of June 25 in Proceedings of the National Academy of Sciences. It was funded by the National Science Foundation Office of International Science and Engineering and the National Geographic Society.

The first of the new species, Icadyptes salasi, stood 5 feet tall and lived about 36 million years ago. The second new species, Perudyptes devriesi, lived about 42 million years ago, was approximately the same size as a living King Penguin (2 ½ to 3 feet tall) and represents a very early part of penguin evolutionary history. Both of these species lived on the southern coast of Peru.

These new penguin fossils are among the most complete yet recovered and call into question hypotheses about the timing and pattern of penguin evolution and expansion. Previous theories held that penguins probably evolved in high latitudes (Antarctica and New Zealand) and then moved into lower latitudes that are closer to the equator about 10 million years ago -- long after significant global cooling that occurred about 34 million years ago.

"We tend to think of penguins as being cold-adapted species," Clarke says, "even the small penguins in equatorial regions today, but the new fossils date back to one of the warmest periods in the last 65 million years of Earth's history. The evidence indicates that penguins reached low latitude regions more than 30 million years prior to our previous estimates."

The new species are the first fossils to indicate a significant and diverse presence of penguins in equatorial areas during a period that predates one of the most important climatic shifts in Earth's history, the transition from extremely warm temperatures in the Paleocene and Eocene Epochs to the development of "icehouse" Earth conditions and permanent polar icecaps. Not only did penguins reach low latitudes during this warmer interval, but they thrived: more species are known from the new Peruvian localities than inhabit those regions today.

By comparing the pattern of evolutionary relationships with the geographic distribution of other fossil penguins, Clarke and colleagues estimate that the two Peruvian species are the product of two separate dispersal events. The ancestors of Perudyptes appear to have inhabited Antarctica, while those of Icadyptes may have originated near New Zealand.

The new penguin specimens are among the most complete yet discovered that show us what early penguins looked like. Both new species had long narrow pointed beaks -- now believed to be an ancestral beak shape for all penguins. Perudyptes devriesi has a slightly longer beak than seen in some living penguins but the giant Icadyptes salasi exhibits a grossly elongated beak with features not known in any extinct or living species. This species' beak is sharply pointed, almost spear-like in appearance, and its neck is robustly built with strong muscle attachment sites. Icadyptes salasi is among the largest species of penguin yet described.

Although these fossils seem to contradict some of what we think we know about the relationship between penguins and climate, Clarke cautions against assuming that just because prehistoric penguins may not have been cold-adapted, living penguins won't be negatively affected by climate change.

"These Peruvian species are early branches off the penguin family tree, that are comparatively distant cousins of living penguins," Clarke says. "In addition, current global warming is occurring on a significantly shorter timescale. The data from these new fossil species cannot be used to argue that warming wouldn't negatively impact living penguins."

Penguin Bones From "Land Of Fire" Rewrite Bird’s Evolution

ScienceDaily (Feb. 14, 2004) — Fossilized bones found in Tierra del Fuego, Argentina, are likely those of the earliest known South American penguin, which probably lived 20 million years earlier than scientists had supposed. The new find doubles the known fossil record of penguins in South America.

That’s the conclusion of Dr. Julia A. Clarke, assistant professor of marine, earth and atmospheric sciences at North Carolina State University, and her colleagues from Argentina, who published their findings in the December 2003 issue of the journal Novitates of the American Museum of Natural History (AMNH).

According to Clarke, the specimen consists of parts of a pelvic girdle and a leg and dates to the Eocene epoch of Earth’s history – about 40 million years ago – sometimes called the “early age of mammals.” Found at Punta Torcida on Tierra del Fuego’s Atlantic coast, the fossilized bones are sufficiently different from known penguin anatomy to rewrite the story of penguin evolution.

Tierra del Fuego, the southernmost portion of the South American continent, means “land of fire” in English. Argentinean geologist Eduardo B. Olivero’s team discovered the fossils in 1999, and Olivero asked Clarke to help identify the bones.

“This early part of the penguin lineage must have arrived in South America during a comparatively warm period in Earth’s history,” said Clarke, “coincident with the beginning of, or just before, a major global cooling trend that occurred in the mid-Eocene. All other penguin fossils date to long after that ‘icehouse’ phase began and after the Antarctic icecap is inferred present.”

The new find may tell a radically different story from previous discoveries about penguins and their prehistoric travels. Despite the popular association of penguins with cold polar regions, said Clarke, species of the birds live near the equators as well. The earliest penguins, then, might have developed in warmer climates, and slowly adapted as their habitats grew icier.

The scientists found portions of a pelvis, a nearly complete right femur, a fragment of the left femur and other bones. Details of the bones, and a careful comparison of them to both fossil and modern penguin bones, allowed them to unravel the evolutionary relationships of the new fossil.

Clarke says that a larger, more comprehensive study of the penguin family tree is necessary before the full story of early penguins in the Land of Fire can be told. But she’s confident that the discovery will help clarify the timing and pattern of penguin diversification.

“This is the first vertebrate from that distant epoch ever found in Tierra del Fuego,” she says. “As modest as these fossilized bones are, they’ll tell us a great deal about the morphological evolution of penguins and the travels of these birds some 40 million years ago on a very different planet Earth.”

Any of various stout flightless marine birds of the family Spheniscidae, of cool regions of the Southern Hemisphere, having flipperlike wings and webbed feet adapted for swimming and diving, and short scalelike feathers that are white in front and black on the back.

Obsolete. The great auk.

[Possibly from Welsh pen gwyn, White Head (name of an island in Newfoundland), great auk : pen, chief, head + gwynn, white.]

Now "ology"--

–ologysuff.

Discourse; expression: phraseology.

Science; theory; study: dermatology; sexology.

[Middle English -logie, from Old French, from Latin -logia, from Greek -logiā (from logos, word, speech) and from -logos, one who deals with (from legein, to speak).]

(again from Answers.com)

So, in a very simplistic sense, we are here to discuss and study the penguin. Penguins have a tendency to rate as very newsworthy subjects, as well as to endear themselves to the hearts of millions.

There are many blogs out there that report current events regarding penguins: everything from penguin toys to penguins at the zoo. There are penguin hockey players and penguin cake ornaments. But little is said regarding the science of penguins and that is the gap I wish to fill. I have a penguin news site on myspace, and also a blog on Blogger that displays and discusses the Gentoo penguins at Gars O'Higgins Station. But neither spot is apropos for science and there is much to be said, as penguins are our canaries in the proverbial coal mine. They will be the doomsayers of global warming, when they dwindle in numbers. They will be the telling ones who will show the first effects of overfishing the oceans.

Whether we see penguins as cute and adorable or the last vestiges of an evolutionary line that stretches back to the Late Cretaceous, they are a most wonderful addition to our lives. How could we ever imagine life without them?